1. Field
This application relates to suspended cable transport systems commonly known as zip lines. More specifically, this application relates to trolleys for zip line or other suspended cable systems which allow riders to maintain control of their speed of descent while traversing along a suspended cable.
2. Prior Art
Common zip lines are thrill-ride systems predominantly utilized in applications for amusement. A common zip line system includes a suspended cable (constructed of aluminum, steel or similar metallic material) stretched between, and rigidly affixed to, separate supporting structures. One end of the suspended cable is affixed to a support structure which is located at an elevation higher than that of the opposite end. The result is a downward slope of the suspended cable. The higher end of the suspended cable is referred to as the beginning-end, and the lower end is referred to as the ending-end.
A common zip line trolley consists of either one or two pulleys affixed to a common pulley housing. A common zip line ride consists of a rider placing a common zip line trolley on top of a suspended cable at the beginning-end. The pulleys of the trolley are placed on top of the suspended cable and a rider holds on to, or is tethered to, the trolley via a conventional safety harness. The downward slope of the suspended cable facilitates a gravitational force which propels the trolley and rider along the suspended cable. The ride begins when the rider disembarks from the beginning-end traversing along the suspended cable. The ride is complete upon the rider reaching the ending-end.
Zip lines are used by individuals at their own personal locations as well as by businesses in commercial applications. Many commercial zip line courses employ the use of multiple suspended cables allowing for a variety of rides for patrons. Common zip line trolleys are most often constructed of steel, or similar rigid material. Unfortunately, they do not afford a rider the ability to control his or her speed of descent while traversing along the suspended cable. Devices and systems similar to zip lines are witnessed within the oil industry relating to lowering endangered personnel from oil derrick towers.
Zip line riders can be classified as one of two types. Type one, commonly referred to as a novice or beginner, typically has minimal experience with zip lines and is apprehensive about riding one. Novices often prefer to traverse along the suspended cable at a relatively slow speed. Type two, commonly referred to as a daredevil, is an experienced zip line rider seeking the ultimate thrill, normally through traversing along the suspended cable at a rapid speed.
Various types of braking systems for common zip lines are known within the art. The most common methods of zip line braking systems presently available include gravity braking, impact braking and frictional braking. None of the braking systems presently available for common zip lines allow a rider control of his or her speed in a safe, economical and easy-to-use manner.
A gravity braking method relies on the natural sag in the suspended cable coupled with the rider's weight to bring he or she to a stop. The ride ends at a point where the rider's momentum ceases to propel the rider along the suspended cable. Most common zip lines designed with this braking method are capable of utilizing slightly more than half of the suspended cable. Additionally, this method of bringing riders to a stop is imprecise and unpredictable in that riders of different weight will each develop a different momentum. As a result, each rider may stop at a different location along the suspended cable. This can complicate and add expense to the manner in which a zip line course designer designs the means for riders to disembark the suspended cable. An additional problem with this braking method is the rider has no control of his or her speed while traversing along the suspended cable. As a result, riders may accelerate to a velocity beyond their comfort level.
Impact braking methods commonly utilize an elastic cord (often a bungee cord or other similar material) along with a small block. The block is affixed close to the ending-end and in a manner such that it can slide freely along the suspended cable. One end of the bungee cord is fastened to the block and the other end is rigidly affixed to a point on the ground. When a rider traversing along the suspended cable makes contact with the block, the bungee cord expands and brings the rider to a stop. Riders can often be slowed to a stop at a rapid deceleration rate and then be snatched backwards along the suspended cable. This is due to the springing function of the elastic cord and is referred to as the “whip-lash effect”. It is an undesirable and potentially unsafe function typical of such an impact braking method. Riders will each have a particular momentum due to their own weight. This will cause the elastic cord to respond differently for each rider. Similar to gravity braking methods, impact braking methods are also unpredictable and often do not allow for full utilization of the suspended cable. Furthermore, riders have no control of their velocity while traversing along the suspended cable.
In addition to elastic cords, rubber tires affixed to the ending-end of a suspended cable are often used as an impact braking method. Rubber tires witness similar results and potential safety hazards as those experienced with elastic cords.
Another method of impact braking includes a person standing on the ground near the ending-end of the suspended cable. This person, known as a brakeman, holds a rope or elastic cord which is attached to a block that can slide along the suspended cable. As the rider intercepts the block, the brakeman restricts the rope's motion, thus slowing the rider, often abruptly. This is another imprecise and unpredictable braking method which can be unsafe for both rider and brakeman. Furthermore, employment of a brakeman is an added expense to a commercial zip line system.
Frictional braking can be the most dangerous among the common zip line braking methods. One form of frictional braking requires the rider to wear a glove. While traversing along the suspended cable, the rider squeezes the suspended cable with the hand wearing the glove. This creates dynamic friction along the suspended cable, thus slowing the rider. This can be dangerous in that the rider can wear a hole through the glove and rub his or her skin along the suspended cable. Another form of frictional braking requires the rider to drag his or her feet along the ground while approaching the ending-end. Both of these methods are unpredictable and dangerous as bodily harm can easily be experienced.
Other braking methods known within the art add considerable expense and complexity to a common zip line. Many methods are rigidly fixed to a particular suspended cable, thus they are not easily transportable to others. They often include a complicated series of additional pulleys and cables which all must work in unison to be fully operational. Should any one piece of such a braking method malfunction, the entire system and rider's safety may be jeopardized.
With regards to common zip line trolleys, most utilize a single point of connection between the trolley and the rider's safety harness. A typical safety harness is normally made of nylon or other safety fabric. A fabric harness, coupled with a single point of connection to the trolley, creates the likelihood a rider's position will twist while traversing along the suspended cable. Often times the rider may be facing sideways or even backwards during the ride due to this twisting effect. This can pose a serious safety hazard since a rider's feet may no longer be facing forward. Common zip line trolleys and safety harnesses allowing riders to twist can be especially dangerous for a zip line system which relies upon riders using their feet to facilitate braking. For these systems, it is imperative for riders to have both feet facing forward and be ready to land accordingly at the end of the ride.
US Patent Application Publication 20110239898 to Brown describes a zip line system kit comprising a trolley of dual frame pieces, an adjustable length seat, a handle assembly and a braking mechanism. The handle assembly is rigidly affixed to the aforementioned dual frame pieces. One particular embodiment of Brown's device includes a small actuator for activating the aforementioned braking mechanism. This braking mechanism is complicated and elaborate in that it includes a series of mechanical interlocks and springs such to provide functionality for riders to either engage or dis-engage the actuator for decreasing velocity. In addition, this braking mechanism as described prevents the ability to quickly and easily remove the trolley from a suspended cable. Furthermore, Brown's device is used in conjunction with a bumper and shock cords or other force absorbing material in order to facilitate speed control. Brown's device is described as a kit system requiring users to mix and match a multitude of features to achieve intended operation.
U.S. Pat. No. 7,966,941 to Brannan describes a trolley intended for use on a suspended cable or zip line. This trolley comprises dual pulleys conjoined via a common housing. In addition, this trolley comprises a handle including hand brake levers. When the rider squeezes the hand brake levers, a frictional force is applied via brake pads directly to the pulleys.
U.S. Pat. Nos. 7,637,213 and 7,404,360 and US Patent Application Publication 20100162917 to Cylvick describe a trolley intended for use on a suspended cable or zip line. This trolley comprises a single pulley with a series of brake pad segments which apply dynamic frictional forces to the suspended cable. One particular embodiment of Cylvick's device relies predominantly upon the weight of the rider for speed control. Once the rider's weight is determined, the trolley is adjusted accordingly prior to the rider embarking upon a ride. Another embodiment of Cylvick's device does allow for a rider to pull a tether while traversing along the suspended cable. This tether operates in conjunction with, and is dependent upon, the rider's weight. The rider pulls the tether which counteracts the effect of the rider's weight on the braking mechanism. Thus, a rider is able to achieve a minimal degree of speed control during the ride. Cylvick's braking mechanism on this trolley utilizes a series of brake pad segments to provide the frictional braking force which is applied to the suspended cable. Replacement of these brake pads can be difficult in that the entire brake assembly must be detached from the trolley and disassembled. Furthermore, this particular trolley can be cumbersome to remove from the suspended cable. It does not afford itself to quick and easy switching among different suspended cables.
U.S. Pat. No. 6,622,634 to Cylvick describes a trolley intended for use on a suspended cable or zip line. This trolley comprises a single pulley with a brake pad which applies frictional forces to the suspended cable. The speed of descent for this device is predetermined and preset based upon the elevation difference between the support structures. Thus, riders of different weights will traverse along the suspended cable at approximately the same speed. However, riders have no control of their speed for the duration of the ride. The braking mechanism of this apparatus also employs a V-shaped trap which assists in applying additional dynamic friction directly to the suspended cable. This trolley can be complicated to remove from the suspended cable in that partial disassembly is required.
U.S. Pat. No. 6,666,773 to Richardson describes a zip line system which applies a frictional force to the suspended cable. The rider's speed of descent is predetermined based upon the rider's weight and does not afford speed control to the rider during the ride. The braking mechanism of this apparatus also employs a V-shaped trap which assists in applying additional dynamic friction directly to the suspended cable.
US Patent Application Publication 20080202375 to Quattlebaum describes a self-driven cable transportation system. Quattlebaum's device is propelled by effort from the rider's feet, unlike a zip line which utilizes gravitational forces to propel riders. The braking system is described vaguely and provides no specifics. It is possible that the intent is to apply dynamic frictional forces in a multitude of fashions. In continuation, Quattlebaum's device could include a braking mechanism such as a wheel cylinder piston, air shock, nitrogen shock, hydraulic disc brake, magnetic disc brake, dynamic brake or shoe brake. These options could be applied in a multitude of manners and thus are significantly different than the rider controlled zip line trolley brake system.
U.S. Pat. No. 5,113,768 to Brown describes a cable car to be used for videography. The brake is applied via a foot pedal and includes a slip-ring collar and other related complicated apparatus. This system is different from the rider controlled zip line trolley brake system as it is foot-actuated and is not intended for thrill-ride or recreational use.
U.S. Pat. No. 4,934,277 to Smith et al. describes an apparatus designed for the safe recovery of individuals stranded upon suspended cables such as ski lifts. A brake shoe is applied directly to the suspended cable and the force applied is dependent upon the rescuer's weight and a predetermined adjustment of the described lever arm. This adjustment must be predetermined and applied prior to the rescuer descending along the suspended cable. The design of this apparatus affords itself to a slow-moving rescue device and not necessarily for a rapid moving recreational zip line trolley.
U.S. Pat. No. 575,528 to Smallwood illustrates a trollocipede with a braking system. However, Smallwood's braking system is applied to the wheel. This is contrary to the rider controlled zip line trolley brake system which applies frictional forces to the suspended cable. Smallwood's device is not intended, or practical for use on a modern zip line system.
U.S. Pat. No. 301,923 to Reisdorff describes a fire escape device used in conjunction with a suspended rope strung from the top of a burning building. The device utilizes a single pulley and the braking mechanism comprises two separate components. The first is a series of outwardly projecting spurs or barbs which embed into the rope to retard the speed of descent. The second is a lever which allows the escapee to apply a frictional force to the side of the pulley, thus further slowing the speed of descent. This device would not operate as intended if used in conjunction with a metallic suspended cable rather than a rope. The outwardly projecting spurs will not embed into a metallic suspended cable as they will with a rope. Thus, this speed-retarding feature cannot be realized on a common zip line system.